I have used power door lock solenoids on several of these trucks.I get late model GM "solenoids" at the junkyard.They arent really solenoids any more,I think they are called screw motors,but they do the same thing as a solenoid. If you keep the inside handles I believe you have to cut the solid rod that runs from the handle to the latch mechanism,and put in a flexible cable. I have never needed poppers on my doors. If the doors are adjusted correctley: the weatherstrip should put enough pressure on the door to pop it open.
